pca9698.c
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/*
* (C) Copyright 2011
* Dirk Eibach, Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Driver for NXP's pca9698 40 bit I2C gpio expander
*/
#include <common.h>
#include <i2c.h>
#include <linux/errno.h>
#include <pca9698.h>
/*
* The pca9698 registers
*/
#define PCA9698_REG_INPUT 0x00
#define PCA9698_REG_OUTPUT 0x08
#define PCA9698_REG_POLARITY 0x10
#define PCA9698_REG_CONFIG 0x18
#define PCA9698_BUFFER_SIZE 5
#define PCA9698_GPIO_COUNT 40
static int pca9698_read40(u8 addr, u8 offset, u8 *buffer)
{
u8 command = offset | 0x80; /* autoincrement */
return i2c_read(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
}
static int pca9698_write40(u8 addr, u8 offset, u8 *buffer)
{
u8 command = offset | 0x80; /* autoincrement */
return i2c_write(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
}
static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value)
{
unsigned byte = gpio / 8;
unsigned bit = gpio % 8;
if (value)
buffer[byte] |= (1 << bit);
else
buffer[byte] &= ~(1 << bit);
}
int pca9698_request(unsigned gpio, const char *label)
{
if (gpio >= PCA9698_GPIO_COUNT)
return -EINVAL;
return 0;
}
void pca9698_free(unsigned gpio)
{
}
int pca9698_direction_input(u8 addr, unsigned gpio)
{
u8 data[PCA9698_BUFFER_SIZE];
int res;
res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
if (res)
return res;
pca9698_set_bit(gpio, data, 1);
return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
}
int pca9698_direction_output(u8 addr, unsigned gpio, int value)
{
u8 data[PCA9698_BUFFER_SIZE];
int res;
res = pca9698_set_value(addr, gpio, value);
if (res)
return res;
res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
if (res)
return res;
pca9698_set_bit(gpio, data, 0);
return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
}
int pca9698_get_value(u8 addr, unsigned gpio)
{
unsigned config_byte = gpio / 8;
unsigned config_bit = gpio % 8;
unsigned value;
u8 data[PCA9698_BUFFER_SIZE];
int res;
res = pca9698_read40(addr, PCA9698_REG_INPUT, data);
if (res)
return -1;
value = data[config_byte] & (1 << config_bit);
return !!value;
}
int pca9698_set_value(u8 addr, unsigned gpio, int value)
{
u8 data[PCA9698_BUFFER_SIZE];
int res;
res = pca9698_read40(addr, PCA9698_REG_OUTPUT, data);
if (res)
return res;
pca9698_set_bit(gpio, data, value);
return pca9698_write40(addr, PCA9698_REG_OUTPUT, data);
}